Determining effective trailer wheelbase length

Abstract

Systems and methods for estimating a length of at least a portion of a trailer that is carried by a tractor. The tractor has a fifth wheel coupling that is configured to be connected to a kingpin of the trailer. The height of the fifth wheel coupling is adjustable by adjustment of an angle of a boom that carries the fifth wheel coupling. The angle of the boom is determined by a sensor. The angle of the trailer is determined by a sensor. The length of at least a portion of the trailer is calculated based on the boom length, the determined boom angle, and the determined trailer angle.

What is claimed is: 
     
       1. A method of determining an effective wheelbase length of a trailer that is carried by an autonomous tractor and is configured to be moved along the ground, wherein the tractor comprises an autonomous driving control system, a fifth wheel coupling that is configured to be connected to a kingpin of the trailer, wherein a height of the fifth wheel coupling is adjustable by adjustment of an angle of a boom that carries the fifth wheel coupling and wherein the boom has a length, and the tractor further comprises a first sensor that is configured to determine an angle of the boom and a second sensor that is configured to determine an angle of the trailer, the method comprising:
 operating the autonomous driving control system to change the height of the fifth wheel coupling and thus change the height of the trailer; 
 using the first sensor to determine the angles of the boom at a plurality of different heights of the fifth wheel coupling and the trailer; 
 using the second sensor to determine the angles of the trailer at the same plurality of different heights of the fifth wheel coupling and the trailer; and 
 using a processor to calculate the effective wheelbase length based on the determined boom angles, the determined trailer angles, and the boom length. 
 
     
     
       2. The method of  claim 1 , wherein the trailer comprises a set of rear wheels carried by a rear axle, and the effective wheelbase length comprises the trailer wheelbase length from the kingpin to a location proximate the rear axle. 
     
     
       3. The method of  claim 1 , wherein using the processor to calculate the effective wheelbase length comprises determining a distance from the fifth wheel coupling to a line that contains an instant center of the trailer relative to the ground. 
     
     
       4. The method of  claim 3 , wherein determining a distance from the fifth wheel coupling to a line that contains the instant center of the trailer relative to the ground comprises determining derivatives of a boom angle and a trailer angle. 
     
     
       5. The method of  claim 4 , wherein the effective wheelbase length is calculated based on the boom length, the boom angle, and the derivatives of the boom angle and the trailer angle. 
     
     
       6. The method of  claim 1 , wherein the trailer has a front landing gear that is configured to support the front of the trailer off of the ground, and wherein the trailer angle is determined by determining an angle of the fifth wheel coupling when the landing gear is off of the ground. 
     
     
       7. The method of  claim 1 , wherein the first sensor comprises a first inclinometer and the second sensor comprises a second inclinometer. 
     
     
       8. The method of  claim 1 , wherein using the first sensor to determine angles of the boom comprises determining changes in the boom angle as the boom is pivoted, using the second sensor to determine angles of the trailer comprises determining changes in the trailer angle as the boom is pivoted, and using the processor to calculate the effective wheelbase length comprises estimating a wheelbase length based on the changes in boom angle, the changes in trailer angle, and the length of the boom. 
     
     
       9. The method of  claim 1 , wherein using the processor to calculate the effective wheelbase length comprises calculating the effective wheelbase length at a plurality of different boom and trailer angles, and storing data that relates to the boom angles, the trailer angles, and the corresponding effective wheelbase lengths. 
     
     
       10. The method of  claim 9 , further comprising using the stored data in the autonomous driving control system by using the autonomous driving control system to transport the trailer by moving the tractor. 
     
     
       11. The method of  claim 10 , further comprising monitoring the trailer angle as the tractor is being moved by the autonomous driving control system, and updating the effective wheelbase length used by the autonomous driving control system as a function of the monitored trailer angle. 
     
     
       12. The method of  claim 10 , further comprising analyzing the stored data that relates to effective wheelbase lengths and determining a boom angle to use for transporting the trailer and an associated effective wheelbase length to use for the autonomous driving control system, wherein the boom angle is determined by identifying a region in the data where a variation of the effective wheelbase length as a function of boom angle is relatively lower than in other regions in the data. 
     
     
       13. The method of  claim 9 , further comprising retrieving from the stored data a predetermined effective wheelbase length that corresponds to at least one of a current boom angle and a current trailer angle. 
     
     
       14. A method of determining an effective wheelbase length of a trailer that is carried by an autonomous tractor and is configured to be moved along the ground, wherein the tractor comprises an autonomous driving control system, a fifth wheel coupling that is configured to be connected to a kingpin of the trailer, wherein a height of the fifth wheel coupling is adjustable by adjustment of an angle of a boom that carries the fifth wheel coupling and wherein the boom has a length, and the tractor further comprises a first sensor that is configured to determine an angle of the boom and a second sensor that is configured to determine an angle of the trailer, the method comprising:
 operating the autonomous driving control system to pivot the boom and thus change the height of the fifth wheel coupling and the height of the trailer; 
 using the first sensor to determine changes in angle of the boom as the boom is pivoted; 
 using the second sensor to determine changes in angle of the trailer as the boom is pivoted; and 
 using a processor to calculate the effective wheelbase length based on the determined changes in boom angle, the determined changes in trailer angle, and the boom length. 
 
     
     
       15. A method of determining an effective wheelbase length of a trailer that is carried by an autonomous tractor and is configured to be moved along the ground, wherein the tractor comprises an autonomous driving control system, a fifth wheel coupling that is configured to be connected to a kingpin of the trailer, wherein a height of the fifth wheel coupling is adjustable by movement of a boom that carries the fifth wheel coupling, and the tractor further comprises a sensor that is configured to determine an angle of the trailer, the method comprising:
 operating the autonomous driving control system to pivot the boom and thus change the height of the fifth wheel coupling and the height of the trailer; 
 determining the height of the fifth wheel coupling at a plurality of different heights of the fifth wheel coupling; 
 using the sensor to determine the angles of the trailer at the same plurality of different heights of the fifth wheel coupling; and 
 using a processor to calculate the effective wheelbase length based on the determined heights of the fifth wheel coupling and the determined trailer angles. 
 
     
     
       16. A system for determining an effective wheelbase length of a trailer that is carried by an autonomous tractor and is configured to be moved along the ground, wherein the tractor comprises a fifth wheel coupling that is configured to be connected to a kingpin of the trailer, wherein a height of the fifth wheel coupling is adjustable by adjustment of an angle of a boom that carries the fifth wheel coupling and wherein the boom has a length, the system comprising:
 an autonomous driving control system that is configured to be operated to change the height of the fifth wheel coupling and thus the height of the trailer; 
 a first sensor for determining angles of the boom at a plurality of different heights of the fifth wheel coupling and the trailer; 
 a second sensor for determining angles of the trailer at the same plurality of different heights of the fifth wheel coupling and the trailer; and 
 a processor that is configured to calculate an effective wheelbase length based on the determined boom angles, the determined trailer angles, and the boom length. 
 
     
     
       17. The system of  claim 16 , wherein calculating the effective wheelbase length comprises determining a distance from the fifth wheel coupling to a line that contains an instant center of the trailer relative to the ground. 
     
     
       18. The system of  claim 17 , wherein determining a distance from the fifth wheel coupling to a line that contains the instant center of the trailer relative to the ground comprises determining derivatives of a boom angle and a trailer angle. 
     
     
       19. The system of  claim 18 , wherein the effective wheelbase length is calculated based on the boom length, the boom angle, and the derivatives of the boom angle and the trailer angle. 
     
     
       20. The system of  claim 16 , wherein the first sensor comprises a first inclinometer and the second sensor comprises a second inclinometer. 
     
     
       21. The method of  claim 1 , wherein the processor is part of the autonomous driving control system. 
     
     
       22. The system of  claim 16 , wherein the processor is part of the autonomous driving control system.